168 ^1 Minimi of Veterinary Physiology. 



medulla; through paralysis the liver becomes gorged with 

 blood, which is followed by sugar in the urine. This view 

 appears to be the correct one, since stimulation of the upper 

 end of the divided pneumogastric is followed by sugar in the 

 urine, and this sugar is also produced by vaso- motor 

 paralysis, the pneumogastric being a controlling nerve of 

 the vaso-motor centre. 



Further Uses of the Liver. 



We have studied two uses of the liver, viz., the forma- 

 tion of bile and the storing up of glycogen ; but we have 

 yet other uses of this gland to detail. 



The material carried by the portal vein to the liver con- 

 tains, besides peptones, some other ultimate products of 

 proteid digestion, viz., leucin and tyrosin ; these are con- 

 veyed to the liver, and the leucin contributes to the forma- 

 tion of urea. 



Carbonate of ammonia is converted in the body into urea 

 and uric acid, and this change occurs in the liver. Pos- 

 sibly many of the antecedents of urea in the body are in the 

 liver converted into this substance. This is a point to be 

 dealt with more fully in the chapter on the urine — all we 

 wish to impress here is the function the liver possesses of 

 converting into urea and uric acid certain nitrogenous 

 products of digestion. 



As the result of proteid decomposition in the intestinal 

 canal, certain aromatic compounds are formed : these are 

 united with sulphuric acid, and got rid of by the kidneys 

 as conjugated sulphuric acids. In this combination the 

 previously poisonous proteid products are converted into 

 non-poisonous ones, and this change is effected in the 

 liver (Jiunge.) 



Here we have a very important function of the liver 

 demonstrated, viz., as a neutralizer of poisons introduced 

 into the blood by the intestines. Many metallic poisons arc 

 also arrested in the liver, notably mercury and arsenic. 



The numerous and complicated changes produced l>\ the 

 liver may thus be summarized : It forms bile, regulates the 



